docs: def add_config_paths(**kwargs):
      """ Add to the pool of available configuration files for BIDSLayout.
  
      Args:
          kwargs: dictionary specifying where to find additional config files.
              Keys are names, values are paths to the corresponding .json file.
  
      Example:
          > add_config_paths(my_config='/path/to/config')
          > layout = BIDSLayout('/path/to/bids', config=['bids', 'my_config'])
      """
  
      for k, path in kwargs.items():
          if not os.path.exists(path):
              raise ValueError(
                  'Configuration file "{}" does not exist'.format(k))
          if k in cf.get_option('config_paths'):
              raise ValueError('Configuration {!r} already exists'.format(k))
  
      kwargs.update(**cf.get_option('config_paths'))
      cf.set_option('config_paths', kwargs)